The present invention relates to a battery box for a plurality of cells in an electrochemical storage battery.
German Patent Specification 28 35 501 discloses a battery box in which, a series of cells of electrochemical stores are arranged one behind the other in rows that are offset in parallel to one another. A circulating-flow channel, formed by a spacing of the cells from one another through which a temperature controlling fluid can flow (the capacity of the electrochemical stores being temperature dependent), is arranged between adjacent cells. The circulating-flow channels are connected both to an inlet channel and to an outlet channel. The inlet channel, which tapers (that is, decreases in size) in the flow direction, is arranged in the vicinity of the box bottom and the outlet channel, which expands in the flow direction, is arranged in the vicinity of the box lid. However, the arrangement of the cells inside the battery box is shown only diagrammatically, and a technical teaching for a device for positioning the cells inside the battery box is not disclosed. If arranged, for example, in the base section of a vehicle, these battery boxes are generally made of sheet metal, which is quite heavy. Furthermore, such a battery box must have a high strength or flexural rigidity, which also increases its weight. Such high weight is especially troublesome, for example, in a battery operated motor vehicle.
The object of the present invention is therefore to develop a battery box in which the cells can be assembled and accommodated with uniform temperature control, while maintaining a high strength or flexural rigidity, and a low weight compared with the total weight of the installed cells.
This object is achieved according to the invention by a battery box in which the bottoms of the cells are placed on step-type ledges, which have a transverse width that is only a fraction of the width of a cell, and are attached to the side walls of the battery box (for example, by gluing, screwing or welding) in order to keep the circulating-flow channels open. The step dimension of each step of the ledge corresponds to the depth of the housing of a cell plus the corresponding clearance of the circulating-flow channel, thereby ensuring the circulating flow of the temperature controlling fluid. Furthermore, the inlet channel is formed at the bottom of the battery box, between the bottoms of the cells and the box bottom; and the outlet channel is formed in an equivalent way between the top of the cells and the box lid.
As disclosed in the prior art, if a plurality of cell rows is arranged adjacent one another, it is advisable to provide a partition between adjacent cell rows, such partition having symmetrical step-type ledges on both sides. As a result, mutual insulation of the cells placed in rows and a further positional fixing of the individual cells is achieved.
So that a cell housing placed on the ledges is fixed by a positive lock in every direction in the plane of the step, it is advantageous to arrange, at the edge of every step at the top of the ledges, a transversely extending spacing rib whose thickness corresponds approximately to the spacing between adjacent cells, and consequently to the corresponding clearance of the circulating-flow channels. These spacing ribs may beneficially be provided in their upper end region with chambers so that the individual cells can be more readily introduced.
Battery boxes with very long rows of cells, or with a plurality of rows arranged alongside one another, may bulge. It 10 is therefore advantageous to mutually stabilize the side walls and/or the partitions by braces which extend transversely to their longitudinal extension, and which, in particular, are arranged at the height of the ledges, so that the flexural rigidity of the battery box is simultaneously increased with a very low increase in mass.
To better secure the position of the individual cells, it may be beneficial to arrange spacing strips for bracing against the cells on the end walls of the battery box which are situated transversely to the cell rows. In addition it may also be beneficial to provide the side walls and/or partitions of the battery box in the region situated between two adjacent cell housings with vertically extending stop strips. Furthermore, the electrical cell connectors of the cells can be of mechanically robust design, so that the cells are also rigidly interconnected at their terminal pillars. If, because of an extended arrangement of rows of cells, such a high weight now results that the ledges might be too highly loaded, it is advisable to brace the ledges against the box bottom. This can be done, on the one hand, by extending the partition down to the box bottom, as a result of which a plurality of inlet channels are simultaneously formed or, on the other hand, by individual column-type supports.
Where a plurality of rows of cells have to be installed in a mutually insulated manner, it is advantageous to form the partitions up to the vicinity of the top of the cells, which also helps to increase the flexural rigidity of the battery box.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.